docs: adds information regarding using bootc extension offline

[cdrage]

docs: adds information regarding using bootc extension offline

What does this PR do?

Adds some information on how to use bootc while offline, specifically
how to download any and all required images in order to use it.

Screenshot / video of UI

N/A, documentation.

What issues does this PR fix or reference?

Part of #2098

How to test this PR?

Read through the docs! :) Pull the images, turn yourself offline, and
then run / try to build them.

Signed-off-by: Charlie Drage [email protected]

[coderabbitai]

📝 Walkthrough

Walkthrough

Added an Offline / Airplane Mode entry and a new offline workflows section to README.md, describing pre-pulling BIB and example images and step-by-step offline build procedures. The offline documentation content is duplicated within the diff.

Changes

Cohort / File(s)	Change Summary
README documentation README.md	Added an "Offline / Airplane Mode" navigation entry and a new offline workflows section covering pre-pulling bootc-image-builder (BIB) images (CentOS, RHEL 9/10), pre-pulling example/base images, example scripts/workflow steps for offline image builds. The offline content is duplicated in the diff.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

• Attention point: Confirm whether the duplicated offline documentation blocks are intentional or should be consolidated.

Pre-merge checks

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: adding documentation about using the bootc extension offline.
Description check	✅ Passed	The description clearly explains the purpose of the PR—adding offline usage documentation for bootc—and includes relevant testing instructions.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between d1db22d and 17390f4.

📒 Files selected for processing (1)

• README.md (2 hunks)

🧰 Additional context used

🪛 LanguageTool

README.md

[grammar] ~305-~305: Ensure spelling is correct
Context: ...module:latest ``` ### Pre-pulling base bootc images You can also pre-pull the base ...

(QB_NEW_EN_ORTHOGRAPHY_ERROR_IDS_1)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (2)

• GitHub Check: linter, formatter, and tests / windows-2022
• GitHub Check: e2e tests

🔇 Additional comments (5)

README.md (5)

19-19: Verify anchor link matches section heading.

The navigation entry references #offline--airplane-mode (lowercase "airplane"), while the heading at line 260 uses "Offline / airplane mode". Ensure the anchor link format correctly matches GitHub's heading ID generation.

Confirm that the navigation link resolves to the correct section heading.

---

260-264: Section structure and overview are clear.

The new section appropriately explains the offline workflow use case and immediately highlights the ISO build limitation, which is important for users planning their workflow.

---

266-279: BIB image pre-pulling commands are well-documented.

The commands appropriately cover the main builder options (CentOS, RHEL 9, RHEL 10) with helpful comments and clear subscription requirements noted.

---

281-303: Example images are comprehensively documented with helpful descriptions.

The six example images cover common use cases (web server, VPN, container management, guest agent, WiFi, kernel modules) with clear registry references and descriptive comments.

---

324-329: Offline workflow steps are clear and logically sequenced.

The four-step workflow (pull online → build image → go offline → build disk images) properly guides users through the offline scenario and aligns with earlier constraints about format support.

[coderabbitai]

⚠️ Potential issue | 🟡 Minor

Fix grammar error: remove possessive apostrophe on line 307.

Line 307 uses possessive "'s" incorrectly in "Containerfile's offline." Should be "Containerfile" without the possessive apostrophe.

Apply this diff to fix the grammar:

-You can also pre-pull the base image(s) you plan to build your own Containerfile's offline.
+You can also pre-pull the base image(s) you plan to use for your own Containerfile offline.

The base image references (CentOS, Fedora, RHEL) are comprehensive and accurate.

🧰 Tools

🪛 LanguageTool

[grammar] ~305-~305: Ensure spelling is correct
Context: ...module:latest ``` ### Pre-pulling base bootc images You can also pre-pull the base ...

(QB_NEW_EN_ORTHOGRAPHY_ERROR_IDS_1)

🤖 Prompt for AI Agents

In README.md around lines 305 to 322, remove the incorrect possessive apostrophe
on line 307 by changing "Containerfile's offline" to "Containerfile offline"
(i.e., delete the apostrophe), then save the file.

[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 17390f4 and 5fe22e6.

📒 Files selected for processing (1)

• README.md (2 hunks)

🧰 Additional context used

🪛 LanguageTool

README.md

[grammar] ~305-~305: Ensure spelling is correct
Context: ...module:latest ``` ### Pre-pulling base bootc images You can also pre-pull the base ...

(QB_NEW_EN_ORTHOGRAPHY_ERROR_IDS_1)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (3)

• GitHub Check: linter, formatter, and tests / macos-14
• GitHub Check: e2e tests
• GitHub Check: linter, formatter, and tests / windows-2022

🔇 Additional comments (3)

README.md (3)

19-19: Navigation entry added correctly. The link formatting to the new offline section is correct and follows existing markdown conventions.

Also applies to: 19-19

---

260-264: Comprehensive offline workflow documentation. The new section is well-structured with clear instructions for pre-pulling images from appropriate registries, and the warning about ISO builds not working offline is important and appropriate.

Also applies to: 266-330

---

260-330: Verify no unintended duplication of offline content.

The AI-generated summary indicates that offline documentation content may appear in multiple locations within the diff. Please confirm that the offline section at lines 260–330 is the only instance and that no unintended duplication was introduced by reviewing the complete diff and searching for duplicate offline-related sections.

[coderabbitai]

⚠️ Potential issue | 🟡 Minor

Fix grammar error: remove possessive apostrophe and clarify sentence.

Line 307 uses an incorrect possessive apostrophe and the sentence structure is awkward. The phrase "build your own Containerfile's offline" should be clarified.

Apply this diff:

-You can also pre-pull the base image(s) you plan to build your own Containerfile's offline.
+You can also pre-pull the base image(s) you plan to use for your own Containerfile offline.

Also applies to: 307-307

🤖 Prompt for AI Agents

In README.md around line 307, the sentence incorrectly uses a possessive
apostrophe ("Containerfile's") and reads awkwardly; remove the possessive and
rephrase to clarify intent, e.g., change the line to something like: "You can
also pre-pull the base image(s) you plan to use when building your Containerfile
so you can build offline." Make sure the updated sentence removes the
apostrophe, uses "use when building" (or similar wording) for clarity, and
preserves the note about pre-pulling images for offline builds.